Such a combustion chamber has coaxial circularly-symmetrical walls extending one inside the other and interconnected at their upstream ends by an annular chamber end wall that has openings for feeding air and for fuel delivery means.
The inner and outer walls of the chamber include inlet openings and for primary air and dilution air, said openings having edges that project into the inside of the chamber in order to improve the penetration of air into the chamber and in order to guide said air into the very core of the combustion area of the chamber.
These air inlet orifices are usually circular in shape and made by die stamping, which has the effect of creating zones of high stress concentration in the edges of the orifices.
When the turbomachine is in operation, the inner and outer walls of the combustion chamber expand thermally and are subjected to high levels of vibration, thereby generating high stresses at the edges of the orifices, which can lead to cracks appearing in said edges, and can thus reduce the lifetime of the combustion chamber.
The combustion chamber walls may also include inclined multiperforations for passing cooling air that are formed at a distance from the projecting edges of the orifices and that do not provide adequate cooling in the immediate vicinity of said orifices. In these zones, the temperatures reached lead to local burning and corrosion of the metal, thereby leading to the appearance of cracks.